TBH mate i think you did a great job, the focus/sharpness problems might be that the lens is a little soft at full zoom and the auto focus is never going to be as quick as a slr lens, im not all that familiar with your camera but in the auto focus settings does it have a contiuous setting of a tracking setting? if so try using that cause other wise the camera will lock on to the subject but not adjust as you pan with the car or as the car is moving towards you, the other thing is you have the camera at full zoom an equivalent of 430mm ish i dont care what anyone says panning with that aint easy to do even a slight movment at your end will be massive at the subject (try a portrait at full zoom at 1/60 hand held its a bugger you cant even breath, unless your names juz and your freakishly steady
) so the softness might have come from that, just practice panning and being fluid with your movments, not sure about the lack of colour, but even auto levels and auto colour can make the world of differnce in photoshop
you should be proud dude you got some great shots
EDIT: you beat me to it paddy